/*
 * Default text - jQuery plugin for html5 dragging files from desktop to browser
 *
 * Author: Weixi Yen
 *
 * Email: [Firstname][Lastname]@gmail.com
 *
 * Copyright (c) 2010 Resopollution
 *
 * Licensed under the MIT license:
 *   http://www.opensource.org/licenses/mit-license.php
 *
 * Project home:
 *   http://www.github.com/weixiyen/jquery-filedrop
 *
 * Version:  0.1.0
 *
 * Features:
 *      Allows sending of extra parameters with file.
 *      Works with Firefox 3.6+
 *      Future-compliant with HTML5 spec (will work with Webkit browsers and IE9)
 * Usage:
 * 	See README at project homepage
 *
 */
;(function($) {
  jQuery.event.props.push("dataTransfer");

  var opts = {},
  default_opts = {
    fallback_id: '',
    url: '',
    refresh: 1000,
    paramname: 'userfile',
    maxfiles: 25,           // Ignored if queuefiles is set > 0
    maxfilesize: 1,         // MB file size limit
    queuefiles: 0,          // Max files before queueing (for large volume uploads)
    queuewait: 200,         // Queue wait time if full
    data: {},
    headers: {},
    drop: empty,
    dragEnter: empty,
    dragOver: empty,
    dragLeave: empty,
    docEnter: empty,
    docOver: empty,
    docLeave: empty,
    beforeEach: empty,
    afterAll: empty,
    rename: empty,
    error: function(err, file, i) {
      alert(err);
    },
    uploadStarted: empty,
    uploadFinished: empty,
    progressUpdated: empty,
    speedUpdated: empty
  },
  errors = ["BrowserNotSupported", "TooManyFiles", "FileTooLarge"],
  doc_leave_timer, 
  stop_loop = false, 
  files_count = 0, 
  files;
  
  function empty() {}

  $.fn.filedrop = function(method) {
    var methods = {
      init : function(options) {
        // Already initialized
        if($(this).data('filedrop') != undefined || $(this).data('filedrop') != null)
          return false;
        
        var tb = new filedropInstance(this, options);
        tb.init();
        $(this).data('filedrop',tb);
      },
      
      destroy : function( ) { 
        $(this).data('filedrop').destroy();
        $(this).data('filedrop',null);
      }
    };
    
    if ( methods[method] ) {
      return methods[method].apply( this, Array.prototype.slice.call( arguments, 1 ));
    } else if ( typeof method === 'object' || ! method ) {
      return methods.init.apply( this, arguments );
    } else {
      $.error( 'Method ' +  method + ' does not exist on jQuery.filedrop' );
    }


    function filedropInstance(element, options) {

      this.init = function() {
        opts = $.extend({}, default_opts, options);

        element.bind('drop.filedrop', drop).bind('dragenter.filedrop', dragEnter).bind('dragover.filedrop', dragOver).bind('dragleave.filedrop', dragLeave);
        $(document).bind('drop.filedrop', docDrop).bind('dragenter.filedrop', docEnter).bind('dragover.filedrop', docOver).bind('dragleave.filedrop', docLeave);

        $('#' + opts.fallback_id).bind('change.filedrop', function(e) {
          opts.drop(e);
          files = e.target.files;
          files_count = files.length;
          upload();
        });
      };
      
      this.destroy = function() {
        element.unbind('.filedrop');
        $(document).unbind('.filedrop');
        $('#' + opts.fallback_id).unbind('.filedrop');
      };

      function drop(e) {
        opts.drop(e);
        files = e.dataTransfer.files;
        if (files === null || files === undefined) {
          opts.error(errors[0]);
          return false;
        }
        files_count = files.length;
        upload();
        e.preventDefault();
        return false;
      }

      function getBuilder(filename, filedata, mime, boundary) {
        var dashdash = '--',
            crlf = '\r\n',
            builder = '';

        if (opts.data) {
          var params = $.param(opts.data).split(/&/);

          $.each(params, function() {
            var pair = this.split(/=/, 2);
            var name = decodeURI(pair[0]);
            var val = decodeURI(pair[1]);

            builder += dashdash;
            builder += boundary;
            builder += crlf;
            builder += 'Content-Disposition: form-data; name="' + name + '"';
            builder += crlf;
            builder += crlf;
            builder += val;
            builder += crlf;
          });
        }

        builder += dashdash;
        builder += boundary;
        builder += crlf;
        builder += 'Content-Disposition: form-data; name="' + opts.paramname + '"';
        builder += '; filename="' + filename + '"';
        builder += crlf;

        builder += 'Content-Type: ' + mime;
        builder += crlf;
        builder += crlf;

        builder += filedata;
        builder += crlf;

        builder += dashdash;
        builder += boundary;
        builder += dashdash;
        builder += crlf;
        return builder;
      }

      function progress(e) {
        if (e.lengthComputable) {
          var percentage = Math.round((e.loaded * 100) / e.total);
          if (this.currentProgress != percentage) {

            this.currentProgress = percentage;
            opts.progressUpdated(this.index, this.file, this.currentProgress);

            var elapsed = new Date().getTime();
            var diffTime = elapsed - this.currentStart;
            if (diffTime >= opts.refresh) {
              var diffData = e.loaded - this.startData;
              var speed = diffData / diffTime; // KB per second
              opts.speedUpdated(this.index, this.file, speed);
              this.startData = e.loaded;
              this.currentStart = elapsed;
            }
          }
        }
      }

      // Respond to an upload
      function upload() {

        stop_loop = false;

        if (!files) {
          opts.error(errors[0]);
          return false;
        }

        var filesDone = 0,
            filesRejected = 0;

        if (files_count > opts.maxfiles && opts.queuefiles === 0) {
          opts.error(errors[1]);
          return false;
        }

        // Define queues to manage upload process
        var workQueue = [];
        var processingQueue = [];
        var doneQueue = [];

        // Add everything to the workQueue
        for (var i = 0; i < files_count; i++) {
          workQueue.push(i);
        }

        // Helper function to enable pause of processing to wait
        // for in process queue to complete
        var pause = function(timeout) {
            setTimeout(process, timeout);
            return;
        }

        // Process an upload, recursive
        var process = function() {

              var fileIndex;

              if (stop_loop) return false;

              // Check to see if are in queue mode
              if (opts.queuefiles > 0 && processingQueue.length >= opts.queuefiles) {

                return pause(opts.queuewait);

              } else {

                // Take first thing off work queue
                fileIndex = workQueue[0];
                workQueue.splice(0, 1);

                // Add to processing queue
                processingQueue.push(fileIndex);

              }

              try {
                if (beforeEach(files[fileIndex]) != false) {
                  if (fileIndex === files_count) return;
                  var reader = new FileReader(),
                      max_file_size = 1048576 * opts.maxfilesize;

                  reader.index = fileIndex;
                  if (files[fileIndex].size > max_file_size) {
                    opts.error(errors[2], files[fileIndex], fileIndex);
                    // Remove from queue
                    processingQueue.forEach(function(value, key) {
                      if (value === fileIndex) processingQueue.splice(key, 1);
                    });
                    filesRejected++;
                    return true;
                  }
                  reader.onloadend = send;
                  reader.readAsBinaryString(files[fileIndex]);

                } else {
                  filesRejected++;
                }
              } catch (err) {
                // Remove from queue
                processingQueue.forEach(function(value, key) {
                  if (value === fileIndex) processingQueue.splice(key, 1);
                });
                opts.error(errors[0]);
                return false;
              }

              // If we still have work to do,
              if (workQueue.length > 0) {
                process();
              }

            };

        var send = function(e) {

          var fileIndex = ((typeof(e.srcElement) === "undefined") ? e.target : e.srcElement).index

          // Sometimes the index is not attached to the
          // event object. Find it by size. Hack for sure.
          if (e.target.index == undefined) {
            e.target.index = getIndexBySize(e.total);
          }

          var xhr = new XMLHttpRequest(),
              upload = xhr.upload,
              file = files[e.target.index],
              index = e.target.index,
              start_time = new Date().getTime(),
              boundary = '------multipartformboundary' + (new Date).getTime(),
              builder;

          newName = rename(file.name);
          mime = file.type
          if (typeof newName === "string") {
            builder = getBuilder(newName, e.target.result, mime, boundary);
          } else {
            builder = getBuilder(file.name, e.target.result, mime, boundary);
          }

          upload.index = index;
          upload.file = file;
          upload.downloadStartTime = start_time;
          upload.currentStart = start_time;
          upload.currentProgress = 0;
          upload.startData = 0;
          upload.addEventListener("progress", progress, false);

          xhr.open("POST", opts.url, true);
          xhr.setRequestHeader('content-type', 'multipart/form-data; boundary=' + boundary);
          xhr.setRequestHeader('X-Requested-With', 'XMLHttpRequest');

          // Add headers
          $.each(opts.headers, function(k, v) {
            xhr.setRequestHeader(k, v);
          });

          xhr.sendAsBinary(builder);

          opts.uploadStarted(index, file, files_count);

          xhr.onload = function() {
            if (xhr.responseText) {
              var now = new Date().getTime(),
                  timeDiff = now - start_time,
                  result = opts.uploadFinished(index, file, jQuery.parseJSON(xhr.responseText), timeDiff);
              filesDone++;

              // Remove from processing queue
              processingQueue.forEach(function(value, key) {
                if (value === fileIndex) processingQueue.splice(key, 1);
              });

              // Add to donequeue
              doneQueue.push(fileIndex);

              if (filesDone == files_count - filesRejected) {
                afterAll();
              }
              if (result === false) stop_loop = true;
            }
          };

        }

        // Initiate the processing loop
        process();

      }

      function getIndexBySize(size) {
        for (var i = 0; i < files_count; i++) {
          if (files[i].size == size) {
            return i;
          }
        }

        return undefined;
      }

      function rename(name) {
        return opts.rename(name);
      }

      function beforeEach(file) {
        return opts.beforeEach(file);
      }

      function afterAll() {
        return opts.afterAll();
      }

      function dragEnter(e) {
        clearTimeout(doc_leave_timer);
        e.preventDefault();
        opts.dragEnter(e);
      }

      function dragOver(e) {
        clearTimeout(doc_leave_timer);
        e.preventDefault();
        opts.docOver(e);
        opts.dragOver(e);
      }

      function dragLeave(e) {
        clearTimeout(doc_leave_timer);
        opts.dragLeave(e);
        e.stopPropagation();
      }

      function docDrop(e) {
        e.preventDefault();
        opts.docLeave(e);
        return false;
      }

      function docEnter(e) {
        clearTimeout(doc_leave_timer);
        e.preventDefault();
        opts.docEnter(e);
        return false;
      }

      function docOver(e) {
        clearTimeout(doc_leave_timer);
        e.preventDefault();
        opts.docOver(e);
        return false;
      }

      function docLeave(e) {
        doc_leave_timer = setTimeout(function() {
          opts.docLeave(e);
        }, 200);
      }

      try {
        if (XMLHttpRequest.prototype.sendAsBinary) return;
        XMLHttpRequest.prototype.sendAsBinary = function(datastr) {
          function byteValue(x) {
            return x.charCodeAt(0) & 0xff;
          }
          var ords = Array.prototype.map.call(datastr, byteValue);
          var ui8a = new Uint8Array(ords);
          this.send(ui8a.buffer);
        }
      } catch (e) {}
        
    } // End of fileDropInstance()
  }; // End of $.fn.filedrop()
})(jQuery);